Process for the preparation of glycolaldehyde

ABSTRACT

Disclosed are catalyst solutions for the hydroformylation of formaldehyde comprising one or more fluorophosphite compounds, rhodium and a hydroformylation solvent comprising at least one N,N-disubstituted amide, N-substituted cyclic amide, or a mixture thereof. Also disclosed are hydroformylation processes wherein formaldehyde is contacted with carbon monoxide, hydrogen one or more fluorophosphite compounds, rhodium and a hydroformylation solvent to produce glycolaldehyde. The fluorophosphite-based catalysts provide good reaction rates and high selectivity to glycolaldehyde.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a divisional application of U.S. application Ser.No. 11/693,542, filed Mar. 29, 2007, which claims the benefit of U.S.Provisional Application Ser. No. 60/827,486, filed Sep. 29, 2006, whichis incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

This invention pertains to catalyst solutions and processes for thehydroformylation of formaldehyde to glycolaldehyde. More specifically,this invention pertains to catalyst solutions that comprise one or morefluorophosphite ligands, rhodium and a hydroformylation solvent, andprocesses in which formaldehyde is contacted with carbon monoxide,hydrogen, one or more fluorophosphite compounds, rhodium and ahydroformylation solvent to produce glycolaldehyde.

DETAILED DESCRIPTION

The rhodium-catalyzed hydroformylation of formaldehyde has traditionallybeen a disfavored process because of the low activity of the rhodiumcatalyst. The reaction rate can be increased by the addition ofpromoters such as amines or strong acids; however, the presence of suchpromoters can lead to the formation of aldol condensation products andother undesirable by-products that can require additional purificationsteps and expense. If the glycolaldehyde is to be used for thepreparation of ethylene glycol, the addition of promoters also canpoison the hydrogenation catalysts used in the conversion ofglycolaldehyde to ethylene glycol. New catalysts are needed for thehydroformylation of formaldehyde that do not require the presence ofpromoters to provide high reaction rates. I have now discovered thatcatalyst solutions that comprise one or more fluorophosphite ligands,rhodium and a hydroformylation solvent provide greatly improved reactionrates for the hydroformylation of formaldehyde to glycolaldehyde withoutthe use of additional promoters. One aspect of the my invention,therefore, is a catalyst solution, comprising:

-   (i) at least one fluorophosphite compound having the general formula    (I):

-   -   wherein R¹ and R² are hydrocarbyl radicals which contain a total        of up to about 40 carbon atoms;

-   (ii) rhodium; and

-   (iii) a hydroformylation solvent comprising at least one    N,N-disubstituted amide, N-substituted cyclic amide, or a mixture    thereof;    wherein the ratio of gram moles fluorophosphite compound to gram    atoms rhodium is about 1:1 to about 100:1.

Another aspect of my invention is a process for the preparation ofglycolaldehyde utilizing a catalyst solution comprising afluorophosphite ligand and rhodium. My invention, therefore, alsoprovides a process for the preparation of glycolaldehyde comprisingcontacting formaldehyde, hydrogen and carbon monoxide with a catalystsolution, comprising:

-   (i) at least one fluorophosphite compound having the general formula    (I):

-   -   wherein R¹ and R² are hydrocarbyl radicals which contain a total        of up to about 40 carbon atoms;

-   (ii) rhodium; and

-   (iii) a hydroformylation solvent;    wherein the ratio of gram moles fluorophosphite compound to gram    atoms rhodium is about 1:1 to about 100:1.

Unless otherwise indicated, all numbers expressing quantities ofingredients, properties such as molecular weight, reaction conditions,and so forth used in the specification and claims are to be understoodas being modified in all instances by the term “about.” Accordingly,unless indicated to the contrary, the numerical parameters set forth inthe following specification and attached claims are approximations thatmay vary depending upon the desired properties sought to be obtained bythe present invention. At the very least, each numerical parametershould at least be construed in light of the number of reportedsignificant digits and by applying ordinary rounding techniques.Further, the ranges stated in this disclosure and the claims areintended to include the entire range specifically and not just theendpoint(s). For example, a range stated to be 0 to 10 is intended todisclose all whole numbers between 0 and 10 such as, for example 1, 2,3, 4, etc., all fractional numbers between 0 and 10, for example 1.5,2.3, 4.57, 6.1113, etc., and the endpoints 0 and 10. Also, a rangeassociated with chemical substituent groups such as, for example, “C₁ toC₅ hydrocarbons”, is intended to specifically include and disclose C₁and C₅ hydrocarbons as well as C₂, C₃, and C₄ hydrocarbons.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains certainerrors necessarily resulting from the standard deviation found in theirrespective testing measurements.

As used in the specification and the claims, the singular forms “a,”“an” and “the” include their plural referents unless the context clearlydictates otherwise. For example, references to a “promoter,” or a“reactor” is intended to include the one or more promoters or reactors.References to a composition or process containing or including “an”ingredient or “a” step is intended to include other ingredients or othersteps, respectively, in addition to the one named.

The terms “containing” or “including”, are synonymous with the term“comprising”, and is intended to mean that at least the named compound,element, particle, or method step, etc., is present in the composition,article, or method, but does not exclude the presence of othercompounds, catalysts, materials, particles, method steps, etc, even ifthe other such compounds, material, particles, method steps, etc., havethe same function as what is named, unless expressly excluded in theclaims.

It is also to be understood that the mention of one or more method stepsdoes not preclude the presence of additional method steps before orafter the combined recited steps or intervening method steps betweenthose steps expressly identified. Moreover, the lettering of processsteps or ingredients is a convenient means for identifying discreteactivities or ingredients and the recited lettering can be arranged inany sequence, unless otherwise indicated.

The term “solution”, as used herein, is understood to mean that thephosphorus compound and rhodium components are substantially (i.e., 95or greater weight percent of the phosphorus compound and rhodium)dissolved in the hydroformylation solvent to form a homogeneous mixture.The term “fluorophosphite”, as used herein, is understood to mean atrivalent phosphorus compound which is substituted with two oxygen atomsand one fluorine atom. The term “ligand”, as used herein, is intended tohave its commonly accepted meaning as would be understood by personshaving ordinary skill in the art, that is a molecule, atom, ion, orgroup of atoms bound to a central atom in a chelate or coordinationcompound. In the present invention, fluorophosphites can serve asligands bound to a central rhodium atom. The term “hydroformylation”, asused herein, also is understood to have its commonly accepted meaning ofa catalytic process in which hydrogen and carbon monoxide are reactedwith a double bond resulting in the net addition of a formyl group andhydrogen across that double bond. The double bond typically is acarbon-carbon double bond but, as in the case of the present invention,also can be the carbon-oxygen double bound of formaldehyde. The term“formaldehyde”, as used herein, is intended to include monomericformaldehyde and any formaldehyde source that is readily converted toformaldehyde under the conditions of the hydroformylation reaction. Forexample, “formaldehyde”, as used herein, would include formaldehyde inits monomeric form as well as its various acetals, hemiacetals, and lowmolecular weight oligomers such as, for example, paraformaldehyde.Similarly, the term “glycolaldehyde”, is intended to include2-hydroxy-acetaldehyde and any derivatives thereof such as, for example,acetals, ethers, hemiacetals, oligomers, and hydrogenated products, thatmay be produced from glycolaldehyde under hydroformylation reactionconditions.

The preparation of glycolaldehyde by the hydroformylation formaldehydecan be carried out by combining formaldehyde with a rhodium catalyst inthe presence of a mixture of hydrogen and carbon monoxide. I have foundthat a specific group of phosphorus acid esters, fluorophosphites, canbe used as the phosphorus ligand in the hydroformylation offormaldehyde. Thus, the ligands for the present invention are trivalentphosphorus compounds having the formula (I):

The hydrocarbyl groups represented by R¹ and R² may be the same ordifferent, separate or combined, and are selected from unsubstituted andsubstituted alkyl, cycloalkyl, aralkyl, and aryl groups containing atotal of up to about 40 carbon atoms. The total carbon content ofsubstituents R¹ and R² preferably is in the range of about 2 to 35carbon atoms. Examples of the alkyl groups which R¹ and/or R² separatelyor individually can represent include ethyl, butyl, pentyl, hexyl,2-ethylhexyl, octyl, decyl, dodecyl, octadecyl and various isomersthereof. The alkyl groups may be substituted, for example, with up totwo substituents such as alkoxy, cycloalkoxy, formyl, alkanoyl,cycloalkyl, aryl, aryloxy, aroyl, carboxyl, carboxylate salts,alkoxycarbonyl, alkanoyloxy, cyano, sulfonic acid, sulfonate salts andthe like. Cyclopentyl, cyclohexyl and cycloheptyl are examples of thecycloalkyl groups R¹ and/or R² individually can represent. Thecycloalkyl groups may be substituted with alkyl or any of thesubstituents described with respect to the possible substituted alkylgroups. Typical examples of alkyl, cycloalkyl, and aralkyl groups whichR¹ and/or R² individually can represent are alkyl radicals containing upto about 8 carbon atoms, benzyl, cyclopentyl, cyclohexyl, andcycloheptyl.

Examples of the aryl groups which R¹ and/or R² individually canrepresent include, but are not limited to, carbocyclic aryl groups suchas phenyl, naphthyl, anthracenyl, and substituted derivatives thereof.For example, R¹ and/or R² individually can represent aryl radicalshaving formulas (II-IV):

wherein R³ and R⁴ may represent one or more substituents independentlyselected from alkyl, alkoxy, halogen, cycloalkoxy, formyl, alkanoyl,cycloalkyl, aryl, aryloxy, aroyl, carboxyl, carboxylate salts,alkoxy-carbonyl, alkanoyloxy, cyano, sulfonic acid, sulfonate salts andthe like. The alkyl moiety of the aforesaid alkyl, alkoxy, alkanoyl,alkoxycarbonyl and alkanoyloxy groups typically contains up to about 8carbon atoms. Although it is possible for m to represent 0 to 5 and forn to represent 0 to 7, the value of each of m and n usually will notexceed 2. Typically, R³ and R⁴ represent lower alkyl groups, i.e.,straight-chain and branched-chain alkyl of up to about 4 carbon atoms,and m and n each represent 0, 1 or 2.

Alternatively, R¹ and R² in combination or collectively may represent adivalent hydrocarbylene group containing up to about 40 carbon atoms,preferably from about 12 to 35 carbon atoms. Examples of such divalentgroups include alkylene of about 2 to 12 carbon atoms, cyclohexylene andarylene. Specific examples of the alkylene and cycloalkylene groupsinclude ethylene, trimethylene, 1,3-butanediyl,2,2-dimethyl-1,3-propanediyl, 1,1,2-triphenylethanediyl,2,2,4-trimethyl-1,3-pentanediyl, 1,2-cyclohexylene, and the like.Examples of the arylene groups which R¹ and R² collectively mayrepresent are given hereinbelow as formulas (V), (VI) and (VII).

The divalent groups that R¹ and R² collectively may represent includeradicals having the formula

wherein

each of A¹ and A² is an arylene radical, e.g., a divalent, carbocyclicaromatic group containing 6 to 10 ring carbon atoms, wherein each esteroxygen atom of fluorophosphite (I) is bonded to a ring carbon atom of A¹and A²;

X is (i) a chemical bond directly between ring carbon atoms of A¹ and A²or (ii) an oxygen atom, a group having the formula —(CH₂)_(y)— wherein yis 2 to 4, or a group having the formula

wherein R⁵ is hydrogen, alkyl or aryl, such as, for example, the arylgroups illustrated by formulas (II), (III) and (IV), and R⁶ is hydrogenor alkyl. The total carbon content of the group —C(R⁵)(R⁶)— normallywill not exceed 20 and, can be in the range of 1 to 8 carbon atoms.Normally, when R¹ and R² collectively represent a divalenthydrocarbylene group, the phosphite ester oxygen atoms, i.e. the oxygenatoms depicted in formula (I), are separated by a chain of atomscontaining at least 3 carbon atoms.

Examples of the arylene groups represented by each of A¹ and A² includethe divalent radicals having the formulas (V-VII):

wherein R³ and R⁴ may represent one or more substituents independentlyselected from alkyl, alkoxy, halogen, cycloalkoxy, formyl, alkanoyl,cycloalkyl, aryl, aryloxy, aroyl, carboxyl, carboxylate salts,alkoxy-carbonyl, alkanoyloxy, cyano, sulfonic acid, sulfonate salts andthe like. The alkyl moiety of such alkyl, alkoxy, alkanoyl,alkoxycarbonyl and alkanoyloxy groups typically contains up to about 8carbon atoms. Although it is possible for p to represent 0 to 4 and forq to represent 0 to 6, the value of each of p and q usually will notexceed 2. R³ and R⁴ preferably represent lower alkyl groups, i.e.,straight-chain and branched-chain alkyl of up to about 4 carbon atoms,and p and q each represent 0, 1 or 2.

In one embodiment, the fluorophosphite esters can be compounds whereinthe fluorophosphite ester oxygen atoms are bonded directly to a ringcarbon atom of a carbocyclic, aromatic group, e.g., an aryl or arylenegroup represented by any of formulas (II) through (VII). When R¹ and R²individually each represents an aryl radical, e.g., a phenyl group, oneor both of the ring carbon atoms that are in a position ortho to thering carbon atoms bonded to the fluorophosphite ester oxygen atom can besubstituted with an alkyl group, especially a branched chain alkyl groupsuch as isopropyl, tert-butyl, tert-octyl and the like. Similarly, whenR¹ and R² collectively represent a radical having the formula,

the ring carbon atoms of arylene radicals A¹ and A² that are in aposition ortho to the ring carbon atoms bonded to the fluorophosphiteester oxygen atom can be substituted with an alkyl group, typically abranched chain alkyl group such as, for example, isopropyl, tert-butyl,tert-octyl and the like. For example, the fluorophosphite esters mayhave the general formula (VIII):

wherein

each R⁷ is halogen or alkyl of 3 to 8 carbon atoms; each R⁸ is hydrogen,halogen, alkyl of 1 to 8 carbon atoms, or alkoxy of 1 to 8 carbon atoms;and X is (i) a chemical bond directly between ring carbon atoms of eachphenylene group to which X is bonded; or (ii) a group having the formula

wherein each of R⁵ and R⁶ is hydrogen or alkyl of 1 to 8 carbon atoms.In one embodiment, for example, the fluorophosphite can have thefollowing formula (IX):

wherein t-Bu is tertiary butyl and Me is methyl. Fluorophosphite (IX) isavailable commercially from Albemarle Corporation under the trademarkETHANOX 398™ (CAS #118337-09-0).

The fluorophosphite compounds of formula (I) may be prepared bypublished procedures or by techniques analogous thereto, See, forexample, the procedures described by Riesel et al., J. Z. Anorg. Allg.Chem., 603, 145 (1991), Tullock et al., J. Org. Chem., 25, 2016 (1960),White et al., J. Am. Chem. Soc., 92, 7125 (1970) and Meyer et al., Z.Naturforsch, Bi. Chem. Sci., 48, 659 (1993) and in U.S. Pat. No.4,912,155. In addition, some fluorophosphite esters of formula (I) areavailable commercially such as, for example, fluorophosphite (IX)discussed above.

Rhodium compounds that may be used as a source of rhodium for the activecatalyst include rhodium(II) or rhodium(III) salts of carboxylic acids,examples of which include di-rhodium tetraacetate dihydrate, rhodium(II)acetate, rhodium(II) isobutyrate, rhodium(II) 2-ethylhexanoate,rhodium(II) benzoate and rhodium(II) octanoate. Also, rhodium carbonylspecies such as Rh₄ (CO)₁₂, Rh₆ (CO)₁₆ and rhodium(I) acetylacetonatedicarbonyl may be suitable rhodium feeds. Additionally, in cases wherethe phosphine moieties of the complex are easily displaced by thefluorophosphite ligands of the present invention, the rhodium componentmay be introduced into the process as rhodium organophosphine complexessuch as, for example, tris(triphenylphosphine) rhodium carbonyl hydride.Less desirable rhodium sources are rhodium salts of strong mineral acidssuch as chlorides, bromides, nitrates, sulfates, phosphates and thelike.

The ratio of gram moles fluorophosphite compound to gram atoms rhodiumin the hydroformylation catalyst solution and hydroformylation processdescribed herein can vary over a wide range. For example, the gram molefluorophosphite:gram atom rhodium ratios may be from about 1:1 to about100:1. Other examples of gram mole fluorophosphite:gram atom rhodiumratios are about 1:1 to about 70:1 and about 1:1 to about 50:1.

The concentration of the rhodium and ligand in the hydroformylationsolvent or reaction mixture is not critical for the successful operationof our invention. As mentioned hereinabove, a gram mole ligand:gram atomrhodium ratio of at least 1:1 normally is maintained in the reactionmixture. The absolute concentration of rhodium in the reaction mixtureor solution may vary from about 1 mg/liter to about 5000 mg/liter ormore. When the process is operated within the practical conditions ofthis invention, the concentration of rhodium in the reaction solutionnormally is in the range of about 20 to about 300 mg/liter.Concentrations of rhodium lower than this range generally do not yieldacceptable reaction rates and/or require reactor operating temperaturesthat are so high as to be detrimental to catalyst stability. Higherrhodium concentrations are not generally used because of the high costof rhodium.

The hydroformylation solvent for the catalyst solution of the inventioncan comprise amides. Amide solvents generally favor the production ofglycolaldehyde over that of methanol and amides which have no freehydrogen on the amido nitrogen atom have been found to favor productionof glycol aldehyde over that of methanol. Thus, in one embodiment of myinvention, the hydroformylation solvent comprises least oneN,N-disubstituted amide or N-substituted cyclic amide. The term“N,N-disubstituted amide”, is understood to mean that the amide nitrogenis attached to two organo substituents. For example, thehydroformylation solvent can comprise at least one N,N-disubstitutedamide having the formula (X)

wherein R⁹ and R¹⁰ are independently selected from alkyl radicalscontaining 1 to 20 carbon atoms, cycloalkyl radicals containing 5 to 20carbon atoms, aralkyl radicals containing 7 to 12 carbon atoms, and arylradicals containing 6 to 12 carbon atoms; and R¹¹ is independentlyselected from hydrogen, alkyl radicals containing 1 to 20 carbon atoms,cycloalkyl radicals containing 5 to 20 carbon atoms, aralkyl radicalscontaining 7 to 12 carbon atoms, and aryl radicals containing 6 to 12carbon atoms. The alkyl, cycloalkyl, aralkyl, and aryl radicals may besubstituted one or more or a mixture of alkyl, alkoxy, cycloalkyl,halogen, or the like, and aralkyl radicals containing 7 to 12 carbonatoms. The amide can be the amide of lower carboxylic acid such as, forexample, formic, acetic, propionic, hexanoic, etc, and the substituentson the nitrogen can be alkyl groups, such as, for example lower alkylgroups. For example, in one embodiment, R⁵ and R¹⁰ can be independentlyselected from methyl, ethyl, propyl, butyl, pentyl, isopentyl, hexyl,and heptyl and R¹¹ is independently selected from hydrogen, methyl,ethyl, propyl, pentyl, and hexyl. There is some variation in selectivityto glycol aldehyde with the variation in the chain length of the acidamide and the substituents on the nitrogen. The acetamides giveparticularly good results. A mixture of amides can be used.

Some specific examples of N,N-disubstituted amides that may be used asthe hydroformylation solvent include N,N-dimethylformamide,N,N-dimethylacetamide, N,N-diethylformamide, N,N-diethylacetamide,N,N-diethyldodecanamide, N,N-dibutyldodecanamide,N-methyl-N-butyldodecanamide, N,N-diethyltetradecanamide,N,N-dicyclohexyldecanamide, N,N-dibutylbenzamide,N,N-dibenzyloctanamide, and combinations of one or more of thesecompounds. The hydroformylation solvent also may comprise a cyclic amidesuch as, for example, N-methyl-2-pyrrolidinone. These compounds areeither commercially available or can be prepared by known reactions. Itis understood that any of the above amides may be used in combinationwith any of the fluorophosphite compounds described above in anycombination and in any ratio with rhodium described herein. For example,the above N,N-disubstituted amides described above and/orN-methyl-2-pyrrolidinone may be used in any combination with thefluorophosphite compounds represented by formulas (VIII) or (IX).

My invention also provides a process for preparing glycolaldehyde whichcomprises contacting formaldehyde, hydrogen and carbon monoxide with acatalyst solution comprising rhodium and a fluorophosphite compound offormula (I) wherein the ratio of gram moles ligand:gram atom rhodium isabout 1:1 to about 100:1.

As described previously, the formaldehyde employed in the process can beutilized in any various forms, including, but not limited to, gaseousformaldehyde, aqueous formaldehyde solutions such as, for example,commercially available formalin containing approximately 40%formaldehyde, trioxane or paraformaldehyde, methylene dicarboxylates,and linear polymers of formaldehyde (i.e., poly(oxymethylene) glycolsand derivatives thereof) formed from the polymerization oroligomerization of formaldehyde in water, alcohols, or other solvents.Thus, the term “formaldehyde”, as used herein in the context of thecurrent specification and claims, is intended to include all the variousforms of formaldehyde described above. In one embodiment, for example,the process may employ paraformaldehyde as the formaldehyde source.

The presence of water in the catalyst solution can reduce the rate ofthe hydroformylation reaction such that it may be desirable to limit theconcentration of water in the catalyst solution. For example, the use ofcommercial formalin, which contains approximately 60 weight percentwater, as a formaldehyde source can severely reduce the rate of thereaction if the concentration of water in the catalyst solution isallowed to become too high. Thus, if water is present in theformaldehyde source, it may be desirable to reduce the overallconcentration of water introduced into the reaction by using a feedstockhaving high concentration of formaldehyde or mixing the aqueousformaldehyde source with a non-aqueous source such as, for example,paraformaldehyde. In one embodiment of the process of the invention, forexample, the catalyst solution can have a water concentration of 10weight percent or less, based on the total weight of the catalystsolution. Other examples of water concentrations in the catalystsolution are 8 weight percent or less, 6 weight percent or less, 4weight percent or less, 2 weight percent or less, and 0.5 weight percentor less.

The fluorophosphite compounds may any of the compounds having thegeneral formula (I) as described hereinabove and in any combination. Forexample, as described previously, R¹ and R² individually can beindependently selected from alkyl radicals of up to 8 carbon atoms,benzyl, cyclopentyl, cyclohexyl, cycloheptyl, and aryl groups havingformulas (II-IV):

wherein R³ and R⁴ are independently selected from alkyl, alkoxy,halogen, cycloalkoxy, formyl, alkanoyl, cycloalkyl, aryl, aryloxy,aroyl, carboxyl, carboxylate salts, alkoxycarbonyl, alkanoyloxy, cyano,sulfonic acid and sulfonate salts in which the alkyl moiety of suchalkyl, alkoxy, alkanoyl, alkoxycarbonyl and alkanoyloxy groups containsup to 8 carbon atoms; m and n each is 0, 1 or 2; and the total carbonatom content of the hydrocarbyl radicals represented by R¹ and R² is 2to 35. In another example, R¹ and R² collectively represent alkylene of2 to 12 carbon atoms, cyclohexylene, an arylene group having theformulas (V-VII):

or a radical having the formula

wherein

each of A¹ and A² is an arylene radical having formula (V), (VI) or(VII) above wherein each ester oxygen atom of fluorophosphite (I) isbonded to a ring carbon atom of A¹ and A²;

X is (i) a chemical bond directly between ring carbon atoms of A¹ andA²; or (ii) an oxygen atom, a group having the formula —(CH₂)_(y)—wherein y is 2 to 4, or a group having the formula

wherein R⁵ is hydrogen, alkyl or aryl; R⁶ is hydrogen or alkyl; and thegroup —C(R⁵)(R⁶)— contains up to 8 carbon atoms; and

wherein R³ and R⁴ are independently selected from alkyl, alkoxy,halogen, cycloalkoxy, formyl, alkanoyl, cycloalkyl, aryl, aryloxy,aroyl, carboxyl, carboxylate salts, alkoxycarbonyl, alkanoyloxy, cyano,sulfonic acid and sulfonate salts in which the alkyl moiety of suchalkyl, alkoxy, alkanoyl, alkoxycarbonyl and alkanoyloxy groups containsup to about 8 carbon atoms; and p and q each is 0, 1 or 2. In yetanother example, the fluorophosphite compound has formula (VIII):

wherein R⁷ represents halogen or C₃ to C₈ alkyl; R⁸ represents hydrogen,halogen, C₁ to C₈ alkyl, or C₁ to C₈ alkoxy; r is 0, 1 or 2; and X is agroup having the formula

wherein R⁵ and R⁶ each are hydrogen or alkyl. In still another example,the fluorophosphite compound has formula (IX):

wherein t-Bu is tertiary butyl and Me is methyl.

The ratio of gram moles fluorophosphite compound to gram atoms rhodiumin the hydroformylation process are as described previously. Forexample, the gram mole fluorophosphite:gram atom rhodium ratios may befrom about 1:1 to about 100:1. Other examples of gram molefluorophosphite:gram atom rhodium ratios are about 1:1 to about 70:1 andabout 1:1 to about 50:1.

The concentration of the rhodium and fluorophosphite ligand in thehydroformylation solvent or reaction mixture is not critical for thesuccessful operation of our invention. As mentioned hereinabove, a grammole ligand:gram atom rhodium ratio of at least 1:1 normally ismaintained in the reaction mixture. The absolute concentration ofrhodium in the reaction mixture or solution may vary from about 1mg/liter to about 5000 mg/liter or more. When the process is operatedwithin the practical conditions of this invention, the concentration ofrhodium in the reaction solution normally is in the range of about 20 toabout 300 mg/liter.

The hydroformylation solvent for the process of the invention can beselected from alkanes, cycloalkanes, alkenes, amides, cycloalkenes,carbocyclic aromatic compounds, esters, ketones, acetals, ethers, andmixtures thereof. As described previously, amides which have no freehydrogen on the amido nitrogen atom have been found to favor productionof glycol aldehyde over that of methanol. Thus, in one embodiment of myhydroformylation process, the hydroformylation solvent comprises leastone N,N-disubstituted amide, at least one N-substituted cyclic amide, ora mixture thereof. Examples of N,N-disubstituted amides include thoseamides having the formula (X)

wherein R⁹ and R¹⁰ are independently selected from alkyl radicalscontaining 1 to 20 carbon atoms, cycloalkyl radicals containing 5 to 20carbon atoms, aralkyl radicals containing 7 to 12 carbon atoms, and arylradicals containing 6 to 12 carbon atoms; and R¹¹ is independentlyselected from hydrogen, alkyl radicals containing 1 to 20 carbon atoms,cycloalkyl radicals containing 5 to 20 carbon atoms, aralkyl radicalscontaining 7 to 12 carbon atoms, and aryl radicals containing 6 to 12carbon atoms. The alkyl, cycloalkyl, aralkyl, and aryl radicals may besubstituted one or more or a mixture of alkyl, alkoxy, cycloalkyl,halogen, or the like, and aralkyl radicals containing 7 to 12 carbonatoms. For example, R⁹ and R¹⁰ can be independently selected frommethyl, ethyl, propyl, butyl, pentyl, isopentyl, hexyl, and heptyl andR¹¹ is independently selected from hydrogen, methyl, ethyl, propyl,pentyl, and hexyl.

Some specific examples of N,N-disubstituted amides that may be used asthe hydroformylation solvent include N,N-dimethylformamide,N,N-dimethylacetamide, N,N-diethylformamide, N,N-diethylacetamide,N,N-diethyldodecanamide, N,N-dibutyldodecanamide,N-methyl-N-butyldodecanamide, N,N-diethyltetradecanamide,N,N-dicyclohexyldecanamide, N,N-dibutylbenzamide,N,N-dibenzyloctanamide, and combinations of one or more of thesecompounds. The hydroformylation solvent also may comprise a cyclic amidesuch as, for example, N-methyl-2-pyrrolidinone. These compounds areeither commercially available or can be prepared by known reactions. Itis understood that any of the above amides may be used in combinationwith any of the fluorophosphite compounds described above in anycombination and in any ratio with the rhodium as described herein. Forexample, the above N,N-disubstituted amides described above and/orN-methyl-2-pyrrolidinone may be used in any combination with thefluorophosphite compounds represented by formulas (VIII) or (IX).

The catalyst solution may comprise other catalyst metals, ligands,solvents, and promoters in addition to the fluorophosphite compounds,rhodium, and hydroformylation solvents described above. For example,Lewis and Bronsted acids such as, for example, ZnCl₂ andp-toluenesulfonic acid, can be added to the catalyst solution to enhancethe rate or selectivity of the hydroformylation reaction. Other examplesof promoters include amine bases such as triethyl amine. Thesepromoters, however, also can have detrimental effects on the catalystand selectivity of the reaction. For example, the presence of strongacids, such as p-toluenesulfonic acid, can cause the eventualdecomposition of the fluorophosphite compound. Similarly, amines cancatalyze the aldol condensation of the product glycolaldehyde withitself to form heavy byproducts.

The reaction conditions used are not critical for the operation of theprocess and conventional hydroformylation conditions normally are used.The process may be carried out at temperatures in the range of about 20°to 200° C., the preferred hydroformylation reaction temperatures arefrom 50° to 135° C. with the most favored reaction temperatures rangingfrom 75° to 125° C. Higher reactor temperatures are not favored becauseof increased rates of catalyst decomposition while lower reactortemperatures result in relatively slow reaction rates. The totalreaction pressure may range from about 1 bar to about 350 bars absolute(about 5000 psig). As another example, the pressure can range from about105 to about 175 bars absolute (about 1500 to 2500 psig).

The hydrogen:carbon monoxide mole ratio in the reactor likewise may varyconsiderably ranging from 10:1 to 1:10 and the sum of the absolutepartial pressures of hydrogen and carbon monoxide may range from 0.5 to350 bars absolute. The ratios of the hydrogen to carbon monoxide in thesynthesis gas (synthesis gas or “syngas” is a mixture of gasescomprising various ratios of carbon monoxide and hydrogen) can bereadily changed by the addition of either hydrogen or carbon monoxide tothe syngas stream.

Another embodiment of the invention is a process for the preparation ofglycolaldehyde consisting essentially of contacting formaldehyde,hydrogen and carbon monoxide with a catalyst solution, consistingessentially of:

-   (i) at least one fluorophosphite compound having the general formula    (I):

-    wherein R¹ and R² collectively represent alkylene of 2 to 12 carbon    atoms, cyclohexylene, an arylene group having the formula

or a radical having the formula

wherein

-   -   each of A¹ and A² is an arylene radical having formula (V), (VI)        or (VII) above wherein each ester oxygen atom of        fluorophosphite (I) is bonded to a ring carbon atom of A¹ and        A²;    -   X is (i) a chemical bond directly between ring carbon atoms of        A¹ and A²; or (ii) an oxygen atom, a group having the formula        —(CH₂)_(y)— wherein y is 2 to 4, or a group having the formula

-   -   -   wherein            -   R⁵ is hydrogen, alkyl or aryl; R⁶ is hydrogen or alkyl;                and the group —C(R⁵)(R⁶)— contains up to 8 carbon atoms;                and                wherein

    -   R³ and R⁴ are independently selected from alkyl, alkoxy,        halogen, cycloalkoxy, formyl, alkanoyl, cycloalkyl, aryl,        aryloxy, aroyl, carboxyl, carboxylate salts, alkoxycarbonyl,        alkanoyloxy, cyano, sulfonic acid and sulfonate salts in which        the alkyl moiety of such alkyl, alkoxy, alkanoyl, alkoxycarbonyl        and alkanoyloxy groups contains up to about 8 carbon atoms; and        p and q each is 0, 1 or 2;

-   (ii) rhodium; and

-   (iii) a hydroformylation solvent consistently essentially of at    least one N,N-disubstituted amide, N-substituted cyclic amide, or a    mixture thereof.    The phrase “consisting essentially of”, as used herein, is intended    to encompass a process for the preparation of glycolaldehyde by    contacting formaldehyde, hydrogen and carbon monoxide with a    catalyst solution that comprises primarily at least one    fluorophosphite ligand in accordance with formula (I) above,    rhodium, and a hydroformylation solvent comprising at least one    N,N-disubstituted amide, N-substituted cyclic amide, or a mixture    thereof. It is understood to exclude any elements that would    substantially alter the essential properties of the hydroformylation    process to which the phrase refers. Although the process of the    present invention is based predominantly on the hydroformylation    solution as described above, it is within the scope of the invention    that the catalyst solution also may contain other catalysts,    solvents, promoters, and ligands, as long as the hydroformylation    reaction rate is not significantly reduced in comparison to the rate    of a catalyst solution, under identical reaction condition, in which    the additional catalysts, solvents, promoters, and ligands are    absent. By “significantly reduced”, it is meant that the reaction    rate is reduced by 70% or more. For example, the addition of    formaldehyde source containing a high level of water at a    concentration that would lead to a reduction in rate by 70% or more    would be excluded from this embodiment of the invention. By    contrast, the addition of a promoter that increases the rate of the    reaction would not be excluded from the scope of the claims.

The above process is understood to include the various embodiments ofthe fluorophosphite compound, rhodium, amide hydroformylation solvent,formaldehyde source, and process conditions described hereinabove. Forexample, the fluorophosphite compound can have formula (VIII):

wherein R⁷ represents halogen or C₃ to C₈ alkyl; R⁸ represents hydrogen,halogen, C₁ to C₈ alkyl, or C₁ to C₈ alkoxy; r is 0, 1 or 2; and X is agroup having the formula

wherein R⁵ and R⁶ each are hydrogen or alkyl. In another example, thefluorophosphite compound has formula (IX):

wherein t-Bu is tertiary butyl and Me is methyl.

The hydroformylation solvent consists essentially of at least oneN,N-disubstituted amide, N-substituted cyclic amide, or combinationthereof. Some specific examples of solvents includeN-methyl-2-pyrrolidinone; N,N-dimethylformamide; N,N-diethylformamide;N,N-diethylacetamide; N,N-diethyldodecanamide; N,N-dibutyldodecanamide;N-methyl-N-butyl-dodecanamide; N,N-diethyltetradecanamide;N,N-dicyclohexyldecanamide, N,N-dibutylbenzamide; andN,N-dibenzyloctanamide. Other solvents may be present, provided theadditional solvents do not significantly reduce the rate of thehydroformylation reaction as described above.

Any of the known hydroformylation reactor designs or configurations maybe used in carrying out the process provided by the present invention.For example, the process also may be practiced in a batchwise manner bycontacting the olefin, hydrogen and carbon monoxide with the presentcatalyst in an autoclave. In another example, a reactor design wherecatalyst and feedstock are pumped into a reactor and allowed to overflowwith product glycolaldehyde, i.e. liquid overflow reactor design, isalso suitable. For example, glycolaldehyde product may be prepared in acontinuous manner with the glycolaldehyde product being removed from thereactor zone as a liquid in combination with the catalyst. Theglycolaldehyde product may be separated from the catalyst byconventional means such as by distillation or extraction and thecatalyst then recycled back to the reactor. A trickle-bed reactor designalso is suitable for this process. It will be apparent to those skilledin the art that other reactor schemes may be used with this invention.The various embodiments of the present invention are further illustratedby the following examples.

EXAMPLES Comparative Example 1

Carbonylation of Formaldehyde with Rhodium and Triphenylphosphine: A 300ml Autoclave Engineer® autoclave was charged with 0.25 Mole ofparaformaldehyde, 50 ml of dimethylacetamide, 1.57 grams oftriphenylphosphine and 0.075 grams of rhodium (1) dicarbonylacetonylacetonate. The reactor was purged with N₂ and charged with a 1:1molar mixture of hydrogen and carbon monoxide to a total pressure of2000 psig. The reactor was stirred and heated to a temperature of 100°C. for a total time of 2 hours. The reactor was cooled and the excesspressure vented. The contents of the autoclave were examined by gaschromatography using an internal standard method. The analysis of thereactor contents showed 32% conversion of the formaldehyde to products.The selectivity to products was 98.0% to glycol aldehyde and 1.2% tomethanol. An additional 0.8% of other products were formed.

Example 1

Hydroformylation catalyst with2,2′-Ethylidenebis(4,6-di-tert-butylphenyl) fluorophosphite (Ethanox398™). The procedure of the comparative example was repeated except that2.91 grams of 2,2′-ethylidenebis(4,6-di-tert-butylphenyl)fluorophosphitewas used as the phosphorus ligand. The ratio of moles fluorophosphiteligand to gram atoms rhodium was approximately 20:1. Analysis of thereaction product showed a 78.3% conversion of formaldehyde to products.The selectivity to products was 99.2% to glycolaldehyde, 0.5% tomethanol and 0.3% to unidentified products.

Example 2

Hydroformylation catalyst with2,2′-methylidenebis(4-tert-butyl-6-methylphenyl)fluorophosphite. Theprocedure of the comparative example was repeated except that 1.36 gramsof 2,2′-methylidenebis(4-tert-butyl-6-methylphenyl)fluorophosphite wasused as the phosphorus ligand. The ratio of moles fluorophosphite ligandto gram atoms rhodium was approximately 12:1. Analysis of the reactionproduct showed a 35% conversion of formaldehyde to products. Theselectivity to products was 95.1% to glycolaldehyde, 1.6% to methanoland 3.3% to unidentified products.

Example 3

Hydroformylation catalyst withO,O′-(2,2′-(3,3,5,5′-tetra-tert-butylbiphenylyl))phosphorofluoridite.The procedure of the comparative example was repeated except that 1.83grams ofO,O′-(2,2′-(3,3′,5,5′-tetra-tert-butylbiphenylyl))phosphorofluoriditewas used as the phosphorus ligand. The ratio of moles fluorophosphiteligand to gram atoms rhodium was approximately 13.7:1. Analysis of therecovered reaction material showed a 49% conversion of formaldehyde toproducts. The selectivity to products was 95.8% to glycolaldehyde, 1.8%to methanol and 2.4% to unidentified products.

Examples 4-27

A series of hydroformylation reactions were carried out under varyingconditions of solvent, ligand concentration, promoter, and formaldehydesource. In all experiments, varying amounts of2,2′-ethylidenebis(4,6-di-tert-butylphenyl)fluorophosphite (ETHANOX™398, available as from Albemarle Corp.) were used as the ligand in thepresence of 30 mg of rhodium as the catalyst. The reactions were carriedout in a 300 ml Autoclave Engineer® autoclave which was charged with0.25 mol of either 40% formalin or paraformaldehyde, solvent, andpromoter as listed in Table 1. The solvents and promoters listed inTable 1 are abbreviated as follows:

DMAC N,N-dimethylacetamide

DMP N,N-dimethylpropionamide

DMI N,N-dimethylisobutyramide

DMO N,N-dimethyloctylamide

DMN N,N-dimethyl-n-butyramide

DIN N,N-diisopropyl-n-butyramide

DHN N,N-di-n-hexyl-n-butyramide

DHI N,N-di-n-hexylisobutyramide

DMH N,N-dimethyl-n-hexamide

DML N,N-dimethyllaurylamide

Et₃N Triethyl amine

TsOH p-Toluenesulfonic acid

Xyl Xylene

Para Paraformaldehyde

The reactor was purged with N₂ and charged with a 1:1 molar mixture ofhydrogen and carbon monoxide to a total pressure of 2000 psig. Thereactor was stirred and heated to a temperature of 100° C. for a totaltime of 1-3 hours. The reactor was then cooled and the excess pressurevented. The contents of the autoclave were examined by gaschromatography using an internal standard method, and the results arepresented in Table 1. No glycolaldehyde product was detected when 40%formalin was used as the source of formaldehyde (Examples 13 and 18). Inaddition, decomposition of the fluorophosphite ligand was observed whenp-toluenesulfonic acid was present as a promoter. The presence oftriethyl amine resulted in the formation of heavy by-products,presumably from the aldol condensation of the glycolaldehyde productwith itself.

TABLE 1 Ligand Solvent H₂CO % Selectivity Time Ex. (g) (amount) Promoter(g) source % Conv to GA (h) 4 1.46 DMAC (50 mL) Et₃N (0.011) para 13.9100 1 5 1.46 DMAC (50 mL) Et₃N (0.022) para 40.9 63.7 1 6 1.46 DMAC (50mL) Et₃N (0.033) para 76 8.7 1 7 0.48 DMAC (50 mL) none para 51.3 84.4 38 1.46 DMAC (50 mL) none para 42.1 89.9 3 9 2.92 DMP (50 mL) none para6.4 98.7 1 10 2.92 DMI (50 mL) none para 15.1 66.3 1 11 2.92 DMO (50 mL)none para 10.8 83.0 1 12 2.92 DIN (50 mL) none formalin 0 n/a 1 13 2.91DMAC (40 mL) none para 21.7 96.6 2 Xyl (10 mL) 14 3.89 DHN (40 g) nonepara 2.4 99.0 1 Xyl (10 mL) 15 3.89 DHI (40 g) none para 3.0 99.0 1 Xyl(10 mL) 16 2.92 DIN (40 g) none para 7.6 86.4 1 Xyl (10 mL) 17 2.92 DIN(20 g) none formalin 0 n/a 1 Xyl (30 mL) 18 1.46 DMAC (50 mL) TsOH(0.10) para 54.7 92.2 1 19 1.46 DMAC (50 mL) TsOH (0.20) para 81.4 81.71 20 1.46 DMAC (50 mL) TsOH (0.40) para 84.4 90.8 3 21 1.46 DML (50 mL)TsOH (0.40) para 16.2 90.1 1 22 1.46 DMH (50 mL) TsOH (0.40) para 24.768.4 1 23 1.46 DMP (50 mL) TsOH (0.40) para 48.3 91.6 1 24 2.92 DMP (50mL) TsOH (0.40) para 40.6 68.5 1 25 4.30 DMH (50 mL) TsOH (0.40) para36.2 73.0 1 26 2.92 DMO (50 mL) TsOH (0.40) para 39.2 84.4 1 27 2.92DMAC (50 mL) ZnCl₂ (0.32) para 34.3 91.3 1

1. A catalyst solution, comprising: (i) at least one fluorophosphitecompound having the general formula (I):

 wherein R¹ and R² are hydrocarbyl radicals which contain a total of upto 40 carbon atoms; (ii) rhodium; and (iii) a hydroformylation solventcomprising at least one N,N-disubstituted amide, N-substituted cyclicamide, or a mixture thereof; wherein the ratio of gram molesfluorophosphite compound to gram atoms rhodium is about 1:1 to about100:1.
 2. The catalyst solution according to claim 1 wherein R¹ and R²individually are independently selected from alkyl radicals of up to 8carbon atoms, benzyl, cyclopentyl, cyclohexyl, cycloheptyl, and arylgroups having formulas (II-IV):

wherein R³ and R⁴ are independently selected from alkyl, alkoxy,halogen, cycloalkoxy, formyl, alkanoyl, cycloalkyl, aryl, aryloxy,aroyl, carboxyl, carboxylate salts, alkoxycarbonyl, alkanoyloxy, cyano,sulfonic acid and sulfonate salts in which the alkyl moiety of suchalkyl, alkoxy, alkanoyl, alkoxycarbonyl and alkanoyloxy groups containsup to 8 carbon atoms; m and n each is 0, 1 or 2; and the total carbonatom content of the hydrocarbyl radicals represented by R¹ and R² is 2to 35 and wherein the ratio of gram moles fluorophosphite compound togram atoms rhodium is about 1:1 to about 70:1.
 3. The catalyst solutionaccording to claim 1 wherein in R¹ and R² collectively represent anarylene group having formulas (V-VII):

or a radical having the formula

wherein each of A¹ and A² is an arylene radical having formula (V), (VI)or (VII) above wherein each ester oxygen atom of fluorophosphite (I) isbonded to a ring carbon atom of A¹ and A²; X is (i) a chemical bonddirectly between ring carbon atoms of A¹ and A²; or (ii) an oxygen atom,a group having the formula —(CH₂)_(y)— wherein y is 2 to 4, or a grouphaving the formula

wherein R⁵ is hydrogen, alkyl, or aryl; R⁶ is hydrogen or alkyl; and thegroup —C(R⁵)(R⁶)— contains up to 8 carbon atoms; and wherein R³ and R⁴are independently selected from alkyl, alkoxy, halogen, cycloalkoxy,formyl, alkanoyl, cycloalkyl, aryl, aryloxy, aroyl, carboxyl,carboxylate salts, alkoxycarbonyl, alkanoyloxy, cyano, sulfonic acid andsulfonate salts in which the alkyl moiety of said alkyl, alkoxy,alkanoyl, alkoxycarbonyl and alkanoyloxy groups contains up to 8 carbonatoms; p and q each are 0, 1 or 2; and the total carbon atom content ofthe radical collectively represented by R¹ and R² is 12 to 35;
 4. Thecatalyst solution according to claim 3 wherein said fluorophosphitecompound has formula (VIII):

wherein R⁷ represents halogen or C₃ to C₈ alkyl; R⁸ represents hydrogen,halogen, C₁ to C₈ alkyl, or C₁ to C₈ alkoxy; r is 0, 1 or 2; and X is agroup having the formula

wherein R⁵ and R⁶ each are hydrogen or alkyl.
 5. The catalyst solutionaccording to claim 4 wherein said fluorophosphite compound has theformula (IX):

wherein t-Bu is tertiary butyl and Me is methyl.
 6. The catalystsolution according to claim 1 wherein said at least oneN,N-disubstituted amide has the following formula (X):

wherein R⁹ and R¹⁰ are independently selected from alkyl radicalscontaining 1 to 20 carbon atoms, cycloalkyl radicals containing 5 to 20carbon atoms, aralkyl radicals containing 7 to 12 carbon atoms, and arylradicals containing 6 to 12 carbon atoms; and R¹¹ is independentlyselected from hydrogen, alkyl radicals containing 1 to 20 carbon atoms,cycloalkyl radicals containing 5 to 20 carbon atoms, aralkyl radicalscontaining 7 to 12 carbon atoms, and aryl radicals containing 6 to 12carbon atoms.
 7. The catalyst solution according to claim 6 wherein R⁹and R¹⁰ are independently selected from methyl, ethyl, propyl, butyl,pentyl, isopentyl, hexyl, and heptyl and R¹¹ is independently selectedfrom hydrogen, methyl, ethyl, propyl, pentyl, and hexyl.
 8. The catalystsolution according to any one of claims 4, 5, or 6 wherein saidhydroformylation solvent comprises N-methyl-2-pyrrolidinone; at leastone N,N-disubstituted amide selected from N,N-dimethylformamide,N,N-dimethylacetamide, N,N-diethylformamide, N,N-diethylacetamide,N,N-diethyldodecanamide, N,N-dibutyldodecanamide,N-methyl-N-butyldodecanamide, N,N-diethyltetradecanamide,N,N-dicyclohexyldecanamide, N,N-dibutylbenzamide, andN,N-dibenzyloctanamide; or a mixture thereof.
 9. The catalyst solutionaccording to any one of claims 4, 5, or 6 wherein said hydroformylationsolvent comprises N,N-dimethylacetamide.